1. Field of the Invention
This invention concerns methods of manufacture of magnetic head devices in which a thin film magnetic head element is formed on one face of a slider.
2. Background Information
As has been disclosed in Laid-Open Patent Application Hei8-30944 and Laid-Open Patent Application Hei10-172125, magnetic head devices of the prior art which are mounted in hard disk devices are fabricated by forming numerous thin film magnetic head elements consisting of multiple component layers in a lattice array on a nearly disc-shaped wafer surface of, for example, Al2O3xe2x80x94TiC, cutting said wafer into individual head blocks, and forming into a slider shape by etching the surface opposing the magnetic recording media consisting of a cut surface.
The aforementioned thin film magnetic head element is formed by vertical layering, using vacuum thin film formation means, of a magnetoresistance effect head (MR head) for reproduction and an inductive head for recording.
Magnetoresistance effect elements, in general, have as principal components a lower magnetic shield layer, lower magnetic gap layer consisting of alumina (Al2O3), magnetoresistance effect element layer (MR element), electrode layer, upper magnetic gap layer consisting of alumina, and upper magnetic shield layer. Inductive heads have as principal components a lower magnetic pole layer, gap layer consisting of alumina, coil layer, insulating layer, and upper magnetic pole layer. These component head layers are formed by successive layering using vacuum thin film formation techniques.
The magnetic gap layers of each head are exposed to the surface of the head block opposing the magnetic recording media, in order to perform writing to or reading from the magnetic recording media.
With the larger capacities and smaller sizes of hard disk devices in recent years, the magnetic disks which are the magnetic recording media are required to have still higher track densities. In consequence of their characteristics, the MR heads used for reproduction are able to accommodate higher densities than are the inductive heads used for recording; but the following problems arise when raising the track densities of inductive heads.
As shown in FIG. 6, inductive heads of the prior art 41 have a wide lower magnetic pole layer 42, a magnetic gap layer 43 formed by layering on top of said layer 42, and a narrow upper magnetic pole layer 44 formed by layering on top of said gap layer 43; the effective track width is determined by the width of said upper magnetic pole layer 44. Hence in order to raise the track density, the upper magnetic pole layer 44 must be formed with a more narrow width, and a magnetic field must be generated in the narrow area between said upper magnetic pole layer 44 and lower magnetic pole layer 42.
However, as track widths become extremely small, the effect of the lateral leakage magnetic field A from the upper magnetic pole layer 44 becomes too large to be neglected. Hence in order to reduce the leakage magnetic field A as much as possible while maintaining the required magnetic field strength, it is desirable that the lower magnetic pole layer 42 be trimmed as in FIG. 7C, and a trimmed part 45 (protrusion) of the same width as the upper magnetic pole layer 44 be formed, in a construction in which said trimmed part 45 effectively acts as the lower magnetic pole.
After forming the upper magnetic pole layer 44 as shown in FIG. 7A, this trimmed part 45 is formed by patterning the gap layer 43 and lower magnetic pole layer 42 using the upper magnetic pole layer 44 as a mask, as shown in FIGS. 7B and 7C.
In the past, alumina (Al2O3) has been widely used as the component material of the gap layer 43; but when ion milling is used in patterning to trim the alumina of the gap layer 43 and the lower magnetic pole layer 42, because of the low milling rate of alumina, after milling the shape is tapered, and the upper and lower magnetic poles 44, 45, facing each other across the gap 43, are not of the same width.
On the other hand, in order to make the widths of the upper and lower magnetic poles 44, 45 identical, it has been proposed that reactive ion etching or some other reactive plasma method be used to selectively pattern the gap layer 43 of alumina vertically, after which ion milling is used to pattern the lower magnetic pole layer 42. Because in this method two types of equipment are usedxe2x80x94equipment for performing reactive ion etching, and equipment for ion millingxe2x80x94equipment costs are increased.
A method of manufacturing a magnetic head device is disclosed. In one embodiment, the method includes forming, on a surface of a wafer and in a lattice array, numerous thin film magnetic head elements including of a plurality of component layers including a magnetic gap layer including a nonmagnetic material. The wafer is cut into individual head blocks. The surface included in a cut surface of said head block to oppose a magnetic recording media is formed by etching into a slider shape. The component material of the magnetic gap layer existing in a region in which the etching is to be performed is removed in advance.